“Although they knew God, they neither glorified him as God nor gave thanks to him.” –Romans 1:21
I’m preparing to preach on John the Baptist. Naturally I’ve been thinking about the meaning of the word “repent,” since it’s part of John’s core message (and was Jesus’ as well).
The gospel of Matthew presents John as somebody “preparing the way of the Lord.” So repentance isn’t the main business for John. It’s preparation. Repentance makes it easier for God to come in and do his work; it straightens out the kinks in his road into our lives.
Repentance isn’t about groveling. In both Greek and Hebrew the word translated “repent” is literally “to turn.” Andrew Walls wrote, “It is not… about the replacement of something old by something new, but about … the turning of the already existing to new account.”  It’s re-orientation. You turn away from something, but equally you turn toward something.
The most fundamental re-orientation, I think, is thankfulness. Not to be thankful, Paul suggests in Romans 1 (see above), is the fundamental basis of alienation from God. To become thankful means turning away from seeing the glass half-empty and toward a focus on what you have. It means turning away from yourself as the center and source (“I deserve this good stuff; I earned it”) and toward the giver.
We all know, every one of us, that we ought to be grateful for waking up each morning, for breathing each breath all day, for lying down safe at night. But while we know we owe thanksgiving—to Somebody, even if we don’t know his name—we don’t offer it. It’s rare that we even think of our good fortune. To repent is to turn away from such thoughtlessness and toward the one who gives all good things. That opens the door for him to come to us and live with us.